反应详情

温度

70 °C

73.5 mL (360 mmol) of a 50% solution of ethyl glyoxalate in toluene then 3.6 ml, (36 mmol) of piperidine and 4.2 mL (72 mmol) of acetic acid are added to a solution of 24 g (180 mmol) of 1,3-dihydro-indol-2-one dissolved in 350 mL of ethanol. The reaction mixture is stirred at 70° C. for 20 hours then concentrated to a quarter by evaporation of the solvents under vacuum. The solid is filtered to give 18.3 g (47%) of (2-oxo-1,2-dihydro-indol-3-ylidene)-ethyl ethanoate in the form of an orange solid. The filtrate is evaporated, then recrystallized from ethanol to give an additional 2.7 g (7%) of (2-oxo-1,2-dihydro-indol-3-ylidene)-ethyl ethanoate in the form of an orange solid.

1. concentrationthen concentrated to a quarter by evaporation of the solvents under vacuum
2. filtrationThe solid is filtered